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Merge pull request #6622 from philljj/zd16426

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tfm fp_exptmod_nct: set result to zero when base is zero
This commit is contained in:
JacobBarthelmeh
2023-07-17 14:29:01 -06:00
committed by GitHub
parent 31aac92635 df58c4dea7
commit 67d35ea48e
1 changed files with 13 additions and 6 deletions
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19
wolfcrypt/src/tfm.c
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@ -3171,14 +3171,21 @@ int fp_exptmod_nct(fp_int * G, fp_int * X, fp_int * P, fp_int * Y)
int x = fp_count_bits (X);
#endif
if (fp_iszero(G)) {
fp_set(G, 0);
/* handle modulus of zero and prevent overflows */
if (fp_iszero(P) || (P->used > (FP_SIZE/2))) {
return FP_VAL;
}
if (fp_isone(P)) {
fp_set(Y, 0);
return FP_OKAY;
}
/* prevent overflows */
if (P->used > (FP_SIZE/2)) {
return FP_VAL;
if (fp_iszero(X)) {
fp_set(Y, 1);
return FP_OKAY;
}
if (fp_iszero(G)) {
fp_set(Y, 0);
return FP_OKAY;
}
#if defined(WOLFSSL_ESP32_CRYPT_RSA_PRI) && \